docs: def create_2D_grid_simple(self, longitude, latitude, year, magnitude,
                                completeness_table, t_f=1., mag_inc=0.1):
          '''
          Generates the grid from the limits using an approach closer to that of
          Frankel (1995)
  
          :param numpy.ndarray longitude:
              Vector of earthquake longitudes
  
          :param numpy.ndarray latitude:
              Vector of earthquake latitudes
  
          :param numpy.ndarray year:
              Vector of earthquake years
  
          :param numpy.ndarray magnitude:
              Vector of earthquake magnitudes
  
          :param numpy.ndarray completeness_table:
              Completeness table
  
          :param float t_f:
              Weichert adjustment factor
  
          :returns:
             Two-dimensional spatial grid of observed rates
  
          '''
          assert mag_inc > 0.
  
          xlim = np.ceil(
              (self.grid_limits['xmax'] - self.grid_limits['xmin']) /
              self.grid_limits['xspc'])
          ylim = np.ceil(
              (self.grid_limits['ymax'] - self.grid_limits['ymin']) /
              self.grid_limits['yspc'])
          ncolx = int(xlim)
          ncoly = int(ylim)
          grid_count = np.zeros(ncolx * ncoly, dtype=float)
          for iloc in range(0, len(longitude)):
              dlon = (longitude[iloc] - self.grid_limits['xmin']) /\
                  self.grid_limits['xspc']
              if (dlon < 0.) or (dlon > xlim):
                  # Earthquake outside longitude limits
                  continue
              xcol = int(dlon)
              if xcol == ncolx:
                  # If longitude is directly on upper grid line then retain
                  xcol = ncolx - 1
              dlat = fabs(self.grid_limits['ymax'] - latitude[iloc]) /\
                  self.grid_limits['yspc']
              if (dlat < 0.) or (dlat > ylim):
                  # Earthquake outside latitude limits
                  continue
              ycol = int(dlat)  # Correct for floating precision
              if ycol == ncoly:
                  # If latitude is directly on upper grid line then retain
                  ycol = ncoly - 1
              kmarker = (ycol * int(xlim)) + xcol
              adjust = _get_adjustment(magnitude[iloc],
                                       year[iloc],
                                       completeness_table[0, 1],
                                       completeness_table[:, 0],
                                       t_f,
                                       mag_inc)
              if adjust:
                  grid_count[kmarker] = grid_count[kmarker] + adjust
          return grid_count